Curly Dock (Rumex crispus) is also known as sour dock, yellow dock, narrow leaf dock. The plant is originally from Eurasia, and is now found throughout the United States. There is also a bitter dock (Rumex obtusifolius) that is very similar.
Description: This perennial plant starts out as a basal rosette of leaves, then develops one or more unbranched stems that grow to about two to four feet tall. The leaves are lance-shaped. Wavy or curly leaf edges give them the impression of being toothed. New stems arise in the spring. It has a taproot that is yellow-orange in color. Clusters of small flowers develop at the top several inches of the stem of the stems. Flowers are yellow green, and then become reddish brown. The top of the dock plant turns brown early in the season, giving it the appearance of being dead. Seeds drop off late summer through winter.
Seeds: Each plant can produce as many as 4,000 seeds that can survive in undisturbed soil for 40 years or more. The seeds are buoyant and can be dispersed by water. The seeds also stick to animal fur and human clothing. Seeds can survive, passing through the digestive system of birds, wildlife, and cattle, but not chickens. Commonly, waterfowl and songbirds eat the seeds.
Where: The most common place to find curly dock is in wet places, especially along road sides, and fields. Dock will be found in other waste places, both in the sun and shade.
What: Dock is in the buckwheat family. Dock contains oxalates, which can be toxic to animals. However, few livestock animals graze on dock. The pollen can cause hayfever. Some people have used the young greens as a food source, boiling the leaves several times to remove the oxalates. If present in a field being tilled, taproot pieces as small as 1 inch can form new plants.
Herbally, curly dock is used in the treatment of skin problems such as psoriasis. Roots have been used to make a black dye. In folk medicine dock is used for fever, scurvy, tumors and cancer.